A boy is having diarrhoea, rhinorrhoea, sweating & lacrimation, what is the most probable diagnosis

Withdrawal Syndrome The onset of withdrawal symptoms occurs typically within 12-24 hours, peaks within 24-72 hours, and symptoms usually subside within 7-10 days of the last dose of opioid. The characteristic symptoms include lacrimation, rhinorrhoea, pupillary dilation, sweating, diarrhoea, yawning, tachycardia, mild hypeension, insomnia, raised body temperature, muscle cramps, generalised body ache, severe anxiety, piloerection, nausea, vomiting and anorexia. There are marked individual differences in the presentation of withdrawal symptoms. Heroin withdrawal syndrome is far more severe than the withdrawal syndrome seen with morphine. Ref: A Sho Textbook of Psychiatry, Niraj Ahuja, 7th Edition, pg. no. 43